


Keys of Reality [CROSSOVER]

by yareyareuwu



Category: Shingeki no Kyojin | Attack on Titan, Sword Art Online (Anime & Manga), Yuri!!! on Ice (Anime), ワンパンマン | One-Punch Man, 斉木楠雄のΨ難 | Saiki Kusuo no Sai-nan | The Disastrous Life of Saiki K.
Genre: Alternate Universe, Armin is awkward, Armin is so pure and confused, Character Death, Crossover, Crossover Pairings, Gen, If you haven't seen any of the animes don't worry, Jesus this story is going to be long, Kaidou is lowkey whipped for Yuri, Kaidou is the edgiest little shit, M/M, Sinon is a good child, Someone is gonna die, Speed-o-sound Sonic has the fattest ego, The ending is gonna be really unexpected, This Is Not Going To Go The Way You Think, Trust me guys I'm the author, Yuri Plisetsky Is A Little Shit, Yuri Plisetsky is a Brat, backstabbing, let's do this shit, many universes
Language: English
Status: In-Progress
Published: 2019-02-11
Updated: 2019-02-11
Packaged: 2019-10-25 23:42:46
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 1
Words: 3,260
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17734904
Author URL: https://archiveofourown.org/users/yareyareuwu/pseuds/yareyareuwu
Summary: SpeedStrengthSmartsStealthShunThese five make up the team that will save this very universe - all that's needed is ten keys, five people and a loyalty and trust beyond anything.Will they make it out alive or will their world crumble?





	Keys of Reality [CROSSOVER]

**Author's Note:**

> Thanks GamerOtakuSama for being the beta reader. Love you, hoe.

The last thing he remembered feeling, was a rock, crushing his ribcage - pieces of the bones stabbing into his lungs. He remembered gasping, tying to gather any air he could. His eyes became dull as yells started to drown out. Some yells were from the fight. Some were from running away. But the most prominent ones were from his two best friends - Eren Jaeger and Mikasa Ackerman. Armin let out his last breath, in the arms of his most trusted friends. His family. Slowly he let his eyes close. But, before they fully shut, a bright light shone, blinding the blonde.

  
  
Armin's drowsy eyes slowly opened, as voices began to clear up.

  
  
"Blondies waking up."

  
  
"You got something against blondes, bitch?!"

  
  
"I-I think it's just a nickname..."

  
  
"Did I ask you?!"

  
  
"Calm down. You're confusing the newcomer."

  
  
Armin slowly rose and the first thing he noticed was the room. Now, he's not quite sure what Eren and Mikasa did with his body, but he is pretty sure there weren't any plans for him to end up in a room like this. Everything was white. The walls, ceiling, floor - everything. Even the furniture - the chairs, the table, the vanity table, the flowers (soil included). But that wasn't the only thing that caught his eye. First of all, the walls had no doors, nor windows. Second of all, there were 10 doors in the middle of the room. And finally, he wasn't alone.

  
  
Dotted around him, and all seeming as confused as he was, were four others.

  
  
One was thin, pale blue swaying hair that was casually short, but there was a tuft of hair tied up on both sides of her forehead, and indigo colored eyes. Her attire consisted of a desert-colored military jacket, bulletproof armor of the same color, and combat boots, as well as a white muffler around her neck.

  
  
Another had blonde, chin-length hair that covers the right side of his face and turquoise eyes. He is shorter than average for his age and has a thin frame. His outfit consisted of his training outfit: a zip-up hoodie with black pants, sneakers, and a zip-up baseball tee styled runner with "Russia" across the chest.

  
  
The third was slim young man with an androgynous appearance. He had long black hair tied up in a topknot, and large gray eyes. A noticeable feature of his are the purple marks underneath his eyes. He wore a tight black bodysuit highlighted by metal plating on his shins, arms, shoulders, chest, and waist, as well as a long purple scarf.

  
  
And the last had blue shaggy and messy hair. He had red eyes, which didn’t make him look like a regular character for an anime. He wore a ripped t-shirt inside with a green and black school uniform. He wore a red bandage - he wears that because he doesn't want his “powers” to destroy things on purpose. He also wore dark green shoes to match with his school uniform appearance.

  
  
Armin blinked slowly in confusion, not recognising anyone around him. Could this be what heaven was? Was he dead? But he felt his heart beating at a normal pace in his chest and he was breathing as normal. One thing was off about this place however - he felt no pain. It should have been passed on to wherever this place was surely. Not even shock would stop him from feeling the pain of a fucking boulder crushing his entire body. So why wasn't he feeling _anything?_

 

Despite still not having come to his senses, he stood up, his legs wobbling.

 

“W-where am I?” Armin stuttered, glancing around at the others.

 

“We don't know. I don't think anyone knows.” The man with the black hair and the violet hood said.

 

There was a scoff and Armin turned to the boy with the Russia jacket on.

 

“Yeah, no shit Sherlock. More importantly, when the fuck am I going to get out of here? I've got some shit to do.” The boy stated in a cold voice, leaning against the wall with crossed arms, pretty obviously annoyed.

 

Everyone stayed quiet for a few seconds, a plain tension in the air around them, until the edgy looking boy, with the turquoise uniform, who was currently squatting on the floor quickly stood up and began to speak to the others.

 

“Uhhh… Why don't we introduce ourselves first, right guys?” He asked in the average mid-teen voice. The boy was shot a sharp glare from everyone in the room apart from Armin, but the boy didn't take any notice of that, seeming too oblivious. “Alright. I'm Kaidou Shun, but they call me Jet Black Wings, the ultimate saviour from the Dark Reunion!” Kaidou exclaimed in a way too enthusiastic voice, sounding like a delusional twelve year old.

 

The man with blond hair snorted and pushed away from his position on the wall, walking over to the others in the group.

 

“Jet Black Wings? Pfft… What kind of name is that? And what the fuck is the Bark Reunion? Do you defend people from dogs? Even my five year old cousin doesn't make up shit like that.” He condescended Kaidou, mocking him. “Anyway, if we're actually doing this, my name is Yuri Plisetsky, or Yurio or whatever you want to fucking call me. I'm basically the Ice Tiger of Russia, the top junior skater.”

 

“And what kind of name is the Ice Tiger of Russia…” The girl uttered, glancing over at Yuri with sharp eyes.

 

Yuri flushed, a spiteful look on his face. “Oi, have you got a problem with that shorty?”

 

“No. Not really. I just think it's funny how you make fun of someone's persona when yours is pretty weird too.” She said calmly, not looking in the slightest bit bothered. “I'm Sinon. Just Sinon. Nice to meet you all.”

 

For the first time in a few minutes, the tallest one there, who was the man with the tight black tracksuit and purple hood, spoke.

 

“I'm Speed-o-sound Sonic. The best ninja you will ever meet. Trust me, I have been perfecting my skills ever since I was young.” Speed-o-sound Sonic trailed off at the end of his sentence, a reminiscent look on his face. “But you can all call me Sonic. I understand that it might be a mouthful to say my entire name.”

 

“Speed-o-sound Sonic, you say? Jesus Christ…” Yuri retorted, rubbing his temples and frowning.

 

Sonic simply shot daggers at Yuri, looking as though he was about to stab him - literally.

 

“Do you want to see how fast I can go, Yurio? It just so happens I can travel faster than the speed of light.”

 

Yuri snorted. “Speed of light my ass... No thanks, you delusional weirdo. I think you'd fit right in with dog saviour over here.”

 

Now at this point, Armin was quite perplexed at everything that was being spoken by the lot of them. Everything was just flying over his head, making him feel more dizzy than he already was before. There were words that Armin had never even heard of being spoken right before him and he could recite the entire dictionary back within The Walls - but this place obviously was nowhere near his homeland.

 

“H-hey, uh, guys! I t-think we should move on, yeah. No hard feelings.” Kaidou stuttered, the tension around the five obviously beginning to get to his head.

 

There was a quick hum of agreement from Sinon, who had been watching the entire ordeal from her standing spot. “Kaidou’s right. Just move on. We’re already in a big enough mess as it is.”

 

At that point, everyone turned to the last remaining person in the group - Armin. From the moment he had arrived, he had been completely silent and was just watching everyone else but now, the attention was on him and what made it worse is that he stuck out like a sore thumb thanks to his uniform and clunky gear.

 

“Oi. You're very quiet, aren't you? Who are you?”

 

Armin stayed completely still, gulping.

 

“Get on with it then! We can't just stand here, we need to get back to our normal lives as soon as possible.” Yuri raised his voice, sounding more pissed off by the second.

 

After a few beats, Armin took a shallow breath and opened his mouth to speak for the first time in a while.

 

“I-I'm Armin Artlet. It's n-nice to meet you.” Armin stuttered, his cheeks tinting a light shade of pink.

 

“At last. Right, now that that's done, let's get into getting the fuck out of this place.” Yuri said looking around the group for confirmation.

 

Sinon nodded. “I agree. But how do you think we can get out of here?” She asked, folding her arms and having a look of thought on her face.

 

“Isn't it obvious? You kids seriously need to take a look around. There's 10 doors right in front of us. Do you think it's just some nice decoration?” Sonic declared pointing over to the 10 doors dotted around the room.

 

“...You're right. Something could be through them. Maybe a door back to our worlds…?” Armin questioned aloud and Sonic looked back at him with a ‘you-know-it’ look.

 

“Exactly.”

 

And just like that, there was something that looked like a black flash of lightning zooming to on a door and in a blink of an eye, Speed-o-sound Sonic appeared in front of the white frame.

 

Armin was utterly lost for words and blankly stared at the man in awe, the other three joining him in astonishment.

 

Sonic began to pull and then push onto the handle, attempting to make the door budge in any way but it didn't even move and inch. The ninja then moved into another door, trying the same thing again but this time throwing his weight against it, but it still didn't work. He tried again and again on other doors, but every single damn door still stood strong.

 

“None of them are moving.”

 

“Yeah, we gathered that from your multiple _failed_ attempts.”

 

Kaidou suddenly shuddered and drew a shaky breath. “I knew it… Doors not opening, a mysterious white room, people from other world's. This must be the work of… the Dark Reunion!” He cried with emphasis as he threw himself into a battle stance.

 

Armin could just feel the cringe climbing onto him as Kaidou shouted with passion:

 

“Take this Dark Reunion! Jet Black Wings from The Judgement Knights of Thunder will destroy you!” Kaidou sped forward and dramatically threw himself against a door, but there was only a light thud and then a pathetic ‘Oof’ sound as Kaidou fell pitifully to the floor.

 

Yuri rolled his eyes, “Idiot.”

 

Sinon began to speak as she watched Kaidou crawl back over to them and stand up.“Perhaps we should just wait it out-”

 

There was a violent neon red light engulfing the room and the white turned to a flashing deep scarlet.

 

“What…” Armin uttered, his eyes darting from corner to corner searching for anything.

 

Suddenly, a thick booming voice echoed all around the room and rang deep into Armin's ears.

 

“Attention, mortals.” The voice was deep and loud and yet there seemed to be no source of where the voice had came from.

 

“Oh my God… It really _is_ the Dark Reunion…” Kaidou whimpered, falling onto his knees and gazing upwards.

 

“Welcome to my world, in which its fate is in your hands. My name is not necessary information for you to hold. You may call me God, but I am no God.”

 

Yuri huffed, not convinced by any whatever was going on around them. “What's this idiot going on about?”

 

“Shut up, Blondie!” Sonic hissed.

 

The voice had a mighty chuckle. “You fools. You don't even know the price of your failure.”

 

“Failure? What do you mean?” Sinon asked, biting her lip.

 

“You mortals have been pulled out of your worlds to face the challenging quest that will determine the fate of all humanity in each of your worlds.” The voice articulated strongly, not even stumbling over a single world.

 

“A challenge, you say…?” Sonic began to have a look on his face that could only be described as pure insanity. “Hah! Fear me! There is no challenge that can beat Speed-o-sound Sonic! My reflexes are faster than the speed of light! This challenge will be conquered!”

 

“Sonic! Shut the fuck up! No one gives a shitting shit!” Yuri yelled, Sonic’s nostrils flaring.

 

“You have quite the ego, Speed-o-sound Sonic. If you are unable to succeed, I guarantee each and every single one of you, that every last living thing will face the most dreadful, agonising death. The entire world will crumble, along with you.”

 

Yuri simply scoffed at this statement. “Yeah, yeah whatever. We all know this is just an empty threat. Just shut up and get me out of here, you useless piece of shit!”

 

“My, my… You really do have a lot to say, don't you, mortal. You call me useless and yet, it's up to me whether you live or perish.” It said, “If you really think that I mean nothing, watch as I eventually kill your precious little Grandfather.”

 

There was silence and Yuri's breath hitched, his gaping mouth shutting tightly with hardly pressed lips.

 

“These pathetic human relationships is what’s keeping all of you here in this world and is the price you will pay if you fail in your quest. The people you value will be gone, just like that. Humans are irrelevant, and yet I'm giving you worthless little creatures a chance to save yourselves from the doom of the universe.”

 

Everyone was in a paralyzed state of tension, fear, confusion and anger. No one in the room could bring themselves to speak.

 

If Armin didn't do this quest, everything he loved and adored - his friends, his life, his world - would be shattered and destroyed just like five years ago when the outer wall was destroyed. Armin couldn't bare all of that again. All of the loss he suffered and the pain of others he saw. What would he do without Eren and Mikasa? Would he really be so selfish as to demolish the lives of others too?

 

“Whatever this mission is… I-I'll do it. I may not be very strong, but I can't just be selfish and not save whatever a universe is…” Armin said with conviction. “I can't lose everything again. It can't happen again.”

 

“Hah! The classic human response. You have made a selfless choice, Armin Artlet.” The voice mocked, sounding like he was enjoying the suffering of the group. “It's not like any of you have any choice anyway.”

 

“So what’s this quest?” Sonic queried.

 

The voice boomed again. “Through each of these doors is a universe and in each universe there is a key you will have to locate and find. If you fail to find the key within the given number of hours or days, one of you will die. But don't assume that this a simple game of hide and seek… You will face challenges within these universes as well.”

 

“Choose a door you want to start with. Remember, you only have one chance. Good luck, humans. I wish you all the best on your route to inevitable failure.”

 

And with those last words, the red pool they were in disappeared and in its place was the simple ivory colour that was there only minutes earlier.

 

“This MUST be a plot from the Dark Reunion! They know that I care about this so they’re going to try and hurt my feelings. Don't worry guys, I've got this. The Dark Reunion will be crushed by the Judgment Knights of Thunder!” Kaidou yelled, puffing his chest out as soon as he stood up.

 

Yuri tutted and kicked the boy in the back of the knee, making Kaidou drop to the ground. “Shut it, you lonely, emo, prebubescent smurf.”

 

“N-now that's a bit rude…” Kaidou whimpered, rubbing the spot where Yuri had viciously kicked him.

 

Armin raised his eyebrow. “What's a smurf?”

 

“Oh my God…”

 

“Whatever a smurf is isn't important right now. What's important is getting on with this stupid quest before the entire universe implodes.” Sinon said before she slowly strode over to a door on the edge of the room and motioned for the others to follow her. “Let's go through this door and hope for the best.” She said, her hand beginning to reach for the handle.

 

“What if it's a trap?” Armin muttered a bit too loud and caused Yuri to turn around and sharply stare at him in astonishment. “R-right…” He quickly waddled over to the rest of the group.

 

Sinon began to turn the silver handle on the door and slowly, it popped and creaked open, a gust of wind thrusting through the frame and blasted onto them. Armin had expected some sort of scenery or something to appear, or at least something that wasn't as bland and would give some contrast to the room he was currently standing in, however, all that was there was just a white space, but blurry. Everything faded into each other, so it only looked like there was just a white empty space.

 

“Who's going in first?” Sonic asked, looking into the space with uncertainty.

 

“Well, it isn't going to be me.” Yuri said, taking a step away from the door.

 

“Same here.” Sinon also took a small glide from the door. “Arckmin what about you?”

 

Armin jerked his head to Sinon. “Uhh… I'll pass. It's Armin by the way.”

 

Kaidou pushed his way to the front, edging onto the other side as he strode past the others. “I'll do it… The Dark Reunion is no match for Jet Black Wings. Mark my words.” He spoke in a deep voice, breathing heavily like a maniac or someone who had been spiked.

 

Charging forward, Kaidou held a mighty a battle cry. But he paused a few metres ahead as he realised that he wasn't in fact going anywhere. It seemed he wasn't even moving at all.

 

“Huh? What's going on? Why aren't I m- AH!” Kaidou finished with a girly scream and his body looked as though it had fallen down a trapdoor as it had completely plummeted downwards without a seconds warning.

 

“What the fuck…” Yuri whispered to himself.

 

“Right, c'mon kids. Let's go before Jet Black Wings does some demonic ritual or diaherra shits his pants.” Sonic ordered, walking into the room whilst the three others followed behind him in a line.

 

"I'm not a kid." Yuri snarled at Sonic who just completely ignored him and recived a look of amusement from Sinon.

 

They waited and in a blink of an eye, they began they began to hurtle downwards in a white spiral, all four of them screaming and shouting as the wind whipped their faces and their bodies fell further and further down into what looked like nothingness. Nothing was there other than a white abyss.

 

Armin's eyes were dry as the wind lapped over his body, the moisture practically being sucked out from them and he basically felt like he was going to vomit.  He squeezed his eyes shut, hoping to regain at least some water, and blinding bright light was replaced with the _somehow_   relaxing black colour of closed eyes.

 

With that, the four landed with painful thud (along with the few cracks of bones) and as Armin's eyes flickered open to reveal a lilac blue sky, he could certainly tell they weren't in the white room any more.  
  

 

 

* * *

 


End file.
